Case of the month: May 1998--a patient with HIV infection and multiple cranial neuritis.

A 36-year old male with a three year history of HIV infection and more recently, CMV retinitis, had several episodes of polyradiculitis with severe bilateral leg pain and urinary retention which resolved slowly over several months. He then presented with high fevers and severe dysphagia with dehydration. Examination showed oral thrush, dyarthric speech and mild memory impairment. Fundoscopic exam showed CMV retinitis and HIV retinopathy. Further examination revealed other cranial nerve signs and leg weakness. MRI scans showed several contrast enhancing abnormalities of cranial nerve roots. The patient died from massive barium aspiration. At autopsy the brain showed multiple CMV cranial neuritis, CMV polyradiculitis and CMV ventriculo-ependymitis. While spinal nerve root involvement by CMV may occur in up to 1% of AIDS patients, involvement of cranial nerves is unusual and CMV infection of multiple cranial nerves is distinctly rare.

Quantification of body fat distribution in the abdomen using computed tomography.

A computed tomographic method was used to assess the pattern of abdominal fat distribution in normal males and females at different abdominal levels. The method permitted site specific calculations of total body volume (TA), total fat volume (TF), subcutaneous fat volume (SF), and intraabdominal fat volume (IF) in each computed tomography scan. The ratio of TF/TA, SF/TF and IF/TF were calculated for the L1, L3, and L5 vertebral levels. Regression analysis of IF versus SF, SF versus TF, IF versus TF, TF versus TA, and TF versus body mass index and age were calculated. A significant linear correlation between the measured variables TA, SF, IF, and TF and between TF and body mass index was found for virtually all correlations attempted at all scanned levels. Females had a higher total fat volume and greater percentage of subcutaneous fat at all levels. Males accumulated more fat intraabdominally than subcutaneously at the L1 and L3 levels. The male-female differences were greatest at L1 and the ratio SF/IF statistically significant at the L1 and L5 levels. Our results demonstrate that computed tomography can noninvasively quantify abdominal fat distribution at various sites. There is an inherent difference in abdominal fat distribution between males and females that is not related to weight. The distribution of body fat in males and females varies markedly from level to level.

Cavernous hemangioma in the diencephalon.

A 32-year-old man with a history of delayed puberty and obesity was seen initially with bitemporal hemianopsia and headache in 1974. Neuroradiologic studies showed a mass in the chiasmatic cistern and hypothalamus. Surgical exploration of the chiasm was unrevealing. Slowly progressive memory loss and intellectual impairment developed. Necropsy in 1978 disclosed a large cavernous hemangioma in the diencephalon.

Posterior cervical spinal cord infarction following vertebral artery dissection.

There are only two reported cases of unilateral posterior cervical spinal cord infarction as a result of vertebral artery dissection. We describe the first reported case of bilateral posterior spinal cord infarction caused by vertebral artery dissection.

Noninvasive diagnosis of extracranial cerebrovascular disease: oculoplethysmography-phonoangiography and directional Doppler ultrasonography.

The ability of two noninvasive diagnostic methods--oculoplethysmography-carotid phonoangiography (OPG/CPA) and directional Doppler ultrasonography--to detect extracranial cerebrovascular disease was examined in 400 consecutive studies. Cerebral arteriography was performed in 74 patients. Transient ischemic attack was the most common indication for study (30%). The OPG was normal in 95% of cases in which the diameter of the lumen of the internal carotid artery (ICA) was less than 60% reduced; the ocular pulse was delayed in 86% of cases with ICA stenosis of 60% or more. The overall diagnostic accuracy of OPG was 93%; CPA did not enhance the accuracy of OPG alone. Supraorbital Doppler tests detected 88% of cases of ICA stenosis of 60% or more, but there was a 13% false-positive rate with ICA stenosis of less than 60%. Supratrochlear Doppler tests had only a 1% false-positive rate, but detected only 48% of significant ICA stenoses. Doppler studies were most often abnormal in the presence of ICA occlusion. Thus, OPG was as sensitive as supraorbital Doppler and more sensitive than supratrochlear Doppler in detecting hemodynamically significant ICA stenoses, without the unacceptable false-positive rate observed with the supraorbital Doppler test.

Positron emission tomography in two cases of childhood epileptic encephalopathy (Lennox-Gastaut syndrome).

Two patients with childhood epileptic encephalopathy were studied by positron emission tomography before and after corpus callosotomy. Preoperatively, both patients showed in the temporal lobe unilateral hypometabolism that is characteristic of interictal epileptic foci. Postoperatively, the first patient had no seizures by the time of scanning, and his temporal lobe metabolism was bilaterally symmetric. Seizure control in the second patient did not improve by the time of scanning, and unilateral temporal hypometabolism persisted. This finding suggests a temporal lobe focus in two patients with Lennox-Gastaut syndrome.

CT body stereotaxic system for placement of needle arrays.

A new CT body stereotaxic system that is particularly suited to multiple placements of needles precisely in parallel is described. By scanning through a right triangle placed on the patient's skin, the stereotaxic method defines an entry point for the first needle placement. An articulating arm is then used to aim the needle at the entry point and hold the needle at the correct angle. The arm can be angled so that the complex approaches from one scan plane to another can be made to place needle arrays through inaccessible lesions, for instance, beneath the diaphragm. Animal and phantom studies have shown that placement of multiple needle arrays in parallel from CT scan data is possible.

Combined cholangiography and cholecystography using sodium iopanoate.

Cholangiography and cholecystography were performed in fasted dogs and human subjects using sodium iopanoate given intraduodenally in doses of 10 and 20 mg/kg. The same studies were performed after intraduodenal administration of fat or after intravenous administration of cholecystokinin (CCK) in dogs and after a fatty meal, to stimulate endogenous release of CCK, in human subjects. In both the animals and human subjects, peak blood iodine concentrations were reached by 30 minutes after iopanoate administration. At a dose of 10 mg/kg, radiographic visualization of both bile ducts and gallbladder was inconsistent. At 20 mg/kg (one-half the clinical dose for standard oral cholecystography,) the common bile duct was visualized within 60 minutes and the gallbladder within 90 minutes. Gallbladder density increased over the next 6 hours. Prior administration of fat or CCK led to earlier and denser gallbladder opacification. The common bile ducts opacified with the use of iopanoate were small in caliber, averaging only 3 mm. This probably reflects the fact that, unlike iodipamide, iopanoate has little or no choleretic effect. Therefore, because it would not increase the volume of bile in the duct, iopanoate would not increase duct size.

A computer-assisted, interactive radiology learning program.

A computer-assisted adjunct to traditional radiology teaching files is described. The student is presented with an image and questions with multiple choice answers. The student's choice leads to additional presentations that reinforce correct responses and provide a critique of incorrect answers. The process is under the control of a teaching script. Requirements for the system included the ability to present high-resolution radiology images along with text; high capacity for storing teaching scripts and images; ease of use by students and authors of teaching scripts; and reasonable cost. A prototype program was written in C-language and run on an IBM PS/2 (IBM Corp., Armonk, NY) with DOS. The hardware also included a 30 megabyte disk drive, an IBM Image Adapter/A and a 14 inch IBM 8514 monitor operating at a 1024 X 768 X 8 bit resolution. Image acquisition was accomplished with a high resolution Pulnix video camera (Pulnix Corp., Tokyo, Japan), with an Imaging Technology (Imaging Technology Corp., Weston, MA) frame grabber, attached to an IBM PC/AT. All hardware is available commercially. A sample teaching file was constructed using a case of ischemic colon after a cecal volvulus. Students used the system and provided a critique. Results indicate that computer-assisted teaching programs can be a valuable addition to traditional teaching methods in radiology.

Magnetic resonance imaging of implanted melanomas before and after chemotherapy. Relation to 31P magnetic resonance spectroscopy and tumor histology.

The early effects of in vivo platinum-rhodamine (PtR) chemotherapy on tumor high-energy phosphorous metabolism was investigated using phosphorus-31 (31P) magnetic resonance spectroscopy (MRS), magnetic resonance imaging (MRI), and histologic examination in a subcutaneously implanted hamster melanoma model. PtR was chosen because of its potential antimitochondrial and antineoplastic properties. All melanomas were clearly observed on both T1- and T2-weighted images (T1WI and T2WI), with viable tumor regions generally characterized by low to intermediate intensity on T1WI and high intensity on T2WI. Necrotic regions were more variable in appearance, depending on the amount of cystic fluid and hemorrhage. No changes were detected on either T1WI or T2WI within 90 minutes of a tumoristatic dose of PtR (40 mg/kg) by visual examination, but slight differences were seen on calculations of relative signal intensities. However, this same dose of PtR caused a 50% drop in tumor ATP and phosphocreatine content (relative to Pi) measured by 31P MRS within 90 minutes of drug injection. Magnetic resonance spectroscopy appears to offer a sensitive means of detecting the earliest biochemical effects of chemotherapeutic agents that are known to affect tumor bioenergetics.

Noninvasive quantitation of liver iron in dogs with hemochromatosis using dual-energy CT scanning.

The concentration of iron deposited in the livers of two dogs with experimentally induced iron overload was determined by use of dual energy computerized tomographic (CT) scanning. A phantom was constructed, containing known amounts of iron-dextran solutions. CT scans of the phantoms, at 80 and 120 kVp, corrected for the response of water, showed a linear relationship between known iron concentrations and difference in CT number at the two scanning energies, with a change of 24 H units per 1000 mg% iron. Using the graph of this linear relationship, the amount of iron in dog liver was predicted, compared with the amount of iron measured from biopsy specimens, and analyzed by neutron activation analysis. A close correlation existed between predicted liver iron and measured iron concentration (r = 0.99). Dual-energy CT scanning appears to provide an accurate, noninvasive method of quantitating liver iron.

Observation on the metabolism of iopanoyl (Telepaque) glucuronide in dogs treated with antibiotics.

The purpose of our investigation was to determine whether iopanoyl glucuronide, the major metabolite of iopanoic acid (Telepaque), undergoes hydrolysis by bacterial beta-glucuronidase in dogs. The conjugated compound was identified and quantitated by elemental analysis, fluorescent excitation analysis, thin-layer chromatography, and high pressure liquid chromatography. The experiments were performed before and after combined antibiotic treatment with neomycin and vancomycin. It was first determined that reabsorption and excretion of sodium iopanoate was only minimally diminished during antibiotic treatment. Known amounts of iopanoyl glucuronide were infused into the small bowel of 4 awake dogs with chronic bile fistula, and bile was collected for 5--8 hours. The excretion of the recirculated conjugated compound was 4--5 times lower during antibiotic treatment. Incubation of ileal fluid with bile containing iopanoyl glucuronide suggested that beta-glucuronidase hydrolyzes the conjugated compound. Hydrolysis was markedly decreased after pretreatment with antibiotics. These findings suggest that the beta-glucuronidase produced by bacteria may be a major mechanism in enterohepatic recirculation of iopanoyl glucuronide. Mechanisms and possible implications are discussed.

CT body stereotaxic instrument for percutaneous biopsy and other interventive procedures: phantom studies.

This article describes a new body stereotaxic system that defines a fiducial point by means of a skin localization device placed directly on the patient. The system uses a rectilinear stereotaxic frame to guide the needles along the calculated path. A method for calculating paths that require angulations from one scan slice to another is described, as well. The system was tested in a foam phantom and shown to be intrinsically accurate in vitro to within 2 mm in both the x and y axis.

Recirculation of iopanoic acid after conjugation in the liver.

The purpose of the investigation was to determine if an enterohepatic recirculation occurred for the metabolite of iopanoic acid. The major metabolite of iopanoic acid (Telepaque) in dog bile is the glucuronide conjugate. The identification and quantitation of glucuronide conjugate was accomplished by elemental analysis, paper chromatography, thin layer chromatography, fluorescent excitation analysis, and high pressure liquid chromatography. The stability of iopanoic acid glucuronide in refrigerated dog bile was confirmed. Known amounts of the glucuronide conjugate were instilled into the duodenum of 8 awake adult dogs, and bile collected for 8 hours. Between 19% and 53% (average 31%) of the administered dose was recovered in bile, thereby documenting the presence of an enterohepatic recirculation of conjugated iopanoic acid. The slow rise and plateau of the excretion curve suggests that either the compound is absorbed slowly, or that absorption depends upon deconjugation in the gut. The implications are discussed.

Evaluation of ultrafast CT scanning of the adult abdomen.

Various measures of image quality were compared from adult abdomen scans obtained with a subsecond computed tomographic (CT) scanner (Imatron Ultrafast C-100) and a conventional third-generation whole-body scanner (GE9800). Forty images from 13 patients scanned within 2 hours of each other on both scanners were evaluated with techniques standardized as much as possible for CT exposure factors and contrast enhancement. Two observers in consensus evaluated matched anatomic levels using standard window width and level settings. Each image was graded on a scale of 1 (worst) to 5 (best) for spatial resolution, image noise, and presence and type of artifacts. Overall image quality also was graded. Averaged scores were compared between the two scanners. In all categories, scores were slightly higher for the GE9800. However, the differences in spatial resolution, presence of artifacts, overall image quality were not significant using the sign test. There was a significant difference, in favor of the GE9800, in image noise. The types of artifacts differed; the GE9800 produced more motion artifacts from bowel and surgical clips and the Imatron C-100 produced more rib shadow artifacts projecting on the liver and spleen. While the GE9800 produced abdominal images of slightly superior quality in adults, the Imatron Ultrafast C-100 was shown to produce images suitable for routine abdominal imaging in adults.

Experimental acute pancreatitis. In vitro magnetic resonance characteristics.

The effect of pancreatitis on magnetic resonance T1 and T2 relaxation times was evaluated in two different models of acute pancreatitis in the rat. Acute edematous pancreatitis was induced by repetitive intraperitoneal injections of the cholecystokinin-analogue caerulein; acute hemorrhage pancreatitis was induced by retrograde infusion of the bile salt sodium taurocholate into the pancreatic duct. T1 and T2 relaxation times were obtained in vitro from fresh pancreatic specimens at 37 degrees C with a 0.25 resistive spectrometer. In both edematous and hemorrhagic pancreatitis, significant prolongation of T1 and T2 was noted as early as 1.5 hours after the initiation of pancreatitis when compared with normal rat pancreas. Maximal prolongation occurred at 7 hours in the caerulein model with T1 of 966 +/- 46 msec (mean +/- SEM) (normal + 278 +/- 12 msec) and T2 of 75.9 +/- 2.9 msec (normal = 32.8 +/- 3.3 msec), and after 6 hours in the bile salt model with T1 of 798 +/- 40 msec and T2 of 92.5 +/- 3.3 msec. After the time point of maximal prolongation, T1 and T2 gradually decreased toward the normal values. The prolongation of T1 and T2 paralleled each other throughout the time course of pancreatitis in both models. The prolongation of both relaxation times correlated closely with pancreatic weight, water content, and amylase concentration in serum and ascites. The present determination of T1 and T2 relaxation times by in vitro spectrometry suggests that magnetic resonance imaging has the potential for detecting early pathologic changes in acute pancreatitis and thus may be helpful for an early clinical diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatobiliary magnetic resonance contrast agents assessed by gadolinium-153 scintigraphy.

A simple method to test new gadolinium complexes potentially useful as enhancement agents for magnetic resonance imaging was developed. Healthy rats underwent scintigraphy with two potential hepatobiliary agents, diethyl IDA and diisopropyl IDA complexed with gadolinium-153. Control products included 153Gd DTPA, 153GdCl3 and technetium-99m diethyl IDA. As shown scintigraphically, 153Gd IDA complexes were partially excreted by urinary and hepatobiliary excretion early after administration. These findings paralleled significant reduction in 1H T1 values of excised livers. However, these agents exhibited prolonged 153Gd whole-body retention. The prolonged tissue distribution of 153Gd activity in animals given 153Gd diethyl IDA did not differ significantly from that observed in animals given GdCl3, and could be attributed to chemical instability or reticuloendothelial uptake. The scintigraphic method permits screening of gadolinium complexes in animals by showing mass balance, kinetics, distribution, and effective stability. Biologic effects of tracer or pharmacologic levels can be compared with those of carrier-free and carrier-added pharmaceuticals.

Properties of free and occupied androgen receptor in rat skeletal muscle cytosol: effect of testosterone.

Our aim was to investigate the effect of a single testosterone (T) injection on the androgen receptor (AR) in rat skeletal muscle (SM) cytosol. The properties of AR were studied in order to establish the protocol for differential determination of free and hormone-occupied AR in SM cytosols from non-hormone-deficient animals. Using the developed ligand-exchange protocol, we demonstrated that injection of T (1 mg/kg) caused alternating changes of the total AR binding. The binding minimum (23% of the control) was measured 1 h after the injection. It was followed by pronounced and lasting elevation of the AR binding. In the control cytosols, AR complexes constituted approximately 25% of the total receptor content. Changes of their relative content immediately after T administration were consistent with rapid nuclear translocation of the AR. Inhibition of protein synthesis by cycloheximide (CHI) injection demonstrated that delayed and lasting increase of the AR binding after T injection partially depended on the stimulated protein synthesis. Altogether, the obtained evidence supports the assumption that the AR mediates elevation of its own gene expression in SM upon administration of T.

Computed tomography and nuclear magnetic resonance imaging of pancreatic islet cell tumors.

Eleven patients with pancreatic islet cell tumors smaller than 2.5 cm were examined by use of computed tomography (CT) and new scanning protocol. Seven of 11 tumors were localized and CT accurately assessed multiple lesions, retroperitoneal invasion, or liver metastases when present. CT is now the initial imaging procedure of choice for diagnosis and staging of islet cell tumors. Nuclear magnetic resonance can distinguish islet cell tumors from normal retroperitoneal structures and appears to be a promising new pancreatic imaging modality.

Prevalence of behavioral risk factors in two American Indian populations in Montana.

Despite great improvements in recent decades, the health status of American Indians continues to lag behind that of other Americans. Continued health improvement will depend largely on changes in individual behavior. However, few data exist on health risk behaviors among American Indians. We used face-to-face interviews to estimate the prevalence of some of these behaviors among American Indians 15-49 years of age in two Montana locations: on the Blackfeet Reservation and in Great Falls. The prevalence of several important health risk behaviors was higher in these populations than in adult Montana residents in general. Tobacco use was very prevalent. Fifty percent of on-reservation women, 62% of off-reservation women, 34% of on-reservation men, and 63% of off-reservation men were smokers at the time of the survey. Thirty-three percent of reservation men used smokeless tobacco. Other risk behaviors of high prevalence included acute heavy drinking (26% to 42% of men); overweight (29% to 41% of females); sedentary lifestyle (46% to 62% of all respondents); and nonuse of seat belts (64% to 79% of all respondents). Tribal leaders and the Indian Health Service are using the survey results to reduce the prevalence of behaviors harming the health of Indian people. In addition to providing valuable information about the surveyed populations, the survey served as a pilot for subsequent surveys of other American Indian groups.